air bag pressure & adjustment of pressure switch (reply)

M

mark grady

New member
May 2, 1998
460
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Richard --

Air bag pressure will vary with the weight of the coach. You are trying to
maintain a fixed height, so more pressure may be required to do that. My '77
Kingsley averages between 80 and 90 pounds in the air bags themselves.

Your tank pressure, which is what you're seeing with that gauge, should be
80 to 120

142# is too much. Back the larger nut off on the big spring in the pressure
switch. 120# is plenty. More than that, and you'll blow out your air bags if
you use the raise setting of the EL I.

If I remember correctly, there is a smaller screw that controls the
differential. Differential is the turn on point for the compressor. Turning
it down (tighter) should make the differential less, but that can also make
the turn off point be higher. You have to kind of fiddle with it to get it
just right.

Based on my experience, you need to have the compressor turn on at 80 to 85#
to have enough tank pressure to get and keep the right ride height with a
heavier load.

Here's the reason: the heavier load equals higher bag pressure.

The leveling valves are calling for more air to be sent to the bags, but the
load on the bags pushes air pressure back into the holding tank. Then, the
compressor doesn't run.

The ride height never goes up when the compressor won't run. The compressor
won't run when the pressure switch is satisfied. The net effect is that the
ride height is too low under load, which throws off your front end steering
geometry and alignment.

All that said, I've assumed you "set level to auto" and are not a "set level
to hold" type of guy. If you're a 'holder' then none of this matters,
because your entire EL I system is turned off. If your rear air bags leak
down any at all, you loose ride height. The system can only level itself in
the 'auto' setting and maintain a constant ride height in the 'auto'
setting.

The owners' manual, the light on the dash and the people on this list are
all divided on the proper operation of the level switch.

I struggled with these concepts for a long time before finally figuring it
out. I could never consistently get the right ride height until I fixed my
pressure switch problem.

Mark Grady
'77 Kingsley
North Webster, IN
mgrady

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
> Sent: Thursday, November 19, 1998 1:26 PM
> To: gmcmotorhome
> Subject: GMC: air bag pressure & adjustment of pressure switch
>
>
> Does anyone know what the air pressure is in the airbags when the coach is
> in "hold" setting at normal height?
>
> The reason I ask is that, after installing the Cinnebar air system upgrade
> kit for Electrolevel I, which includes an in-line gauge, I discovered that
> my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
> at 100 and off at 120 according to the manuals.)
>
> If I adjust the pressure switch by backing off the adjusting nut
> so that the
> compressor turns off at 120psi, that will also reduce the
> pressure at which
> the compressor cycles back on, will it not?
>
> I'm wondering if the system will still function normally with the lower
> cut-in pressure.
>
> Dick Guthart
> '77 Birchaven (still ugly but getting closer to mechanically restored)
>
 
Some information about your problem with the air system.

1. the pressure in the air tank for an power level or Electron level 1
system ranges from 100psi (will turn on the compressor) to 120psi
(compressor shutoff).

2. If you want to lower the high pressure setting back off the large nut
(not turn it in) on the large spring. By playing with the small screw
(differential setting) and the large nut you should be able to get the
compressor to go on at 100psi and off at 120psi. The small screw has nothing
to do with the low pressure setting.

3. The air has no way to get back into the tank since the power level or
electro level contol valves or solenoids which ever is the case restricts it.

4. The manuals are very specific about not driving with the controls in
hold. Depending on the driving conditions, speed etc an overload condition
can develop on the front tires.

Hope this helps.

>Richard --
>
>Air bag pressure will vary with the weight of the coach. You are trying to
>maintain a fixed height, so more pressure may be required to do that. My '77
>Kingsley averages between 80 and 90 pounds in the air bags themselves.
>
>Your tank pressure, which is what you're seeing with that gauge, should be
>80 to 120
>
>142# is too much. Back the larger nut off on the big spring in the pressure
>switch. 120# is plenty. More than that, and you'll blow out your air bags if
>you use the raise setting of the EL I.
>
>If I remember correctly, there is a smaller screw that controls the
>differential. Differential is the turn on point for the compressor. Turning
>it down (tighter) should make the differential less, but that can also make
>the turn off point be higher. You have to kind of fiddle with it to get it
>just right.
>
>Based on my experience, you need to have the compressor turn on at 80 to 85#
>to have enough tank pressure to get and keep the right ride height with a
>heavier load.
>
>Here's the reason: the heavier load equals higher bag pressure.
>
>The leveling valves are calling for more air to be sent to the bags, but the
>load on the bags pushes air pressure back into the holding tank. Then, the
>compressor doesn't run.
>
>The ride height never goes up when the compressor won't run. The compressor
>won't run when the pressure switch is satisfied. The net effect is that the
>ride height is too low under load, which throws off your front end steering
>geometry and alignment.
>
>All that said, I've assumed you "set level to auto" and are not a "set level
>to hold" type of guy. If you're a 'holder' then none of this matters,
>because your entire EL I system is turned off. If your rear air bags leak
>down any at all, you loose ride height. The system can only level itself in
>the 'auto' setting and maintain a constant ride height in the 'auto'
>setting.
>
>The owners' manual, the light on the dash and the people on this list are
>all divided on the proper operation of the level switch.
>
>I struggled with these concepts for a long time before finally figuring it
>out. I could never consistently get the right ride height until I fixed my
>pressure switch problem.
>
>Mark Grady
>'77 Kingsley
>North Webster, IN
>mgrady
>
>
>> -----Original Message-----
>> From: owner-gmcmotorhome
>> [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
>> Sent: Thursday, November 19, 1998 1:26 PM
>> To: gmcmotorhome
>> Subject: GMC: air bag pressure & adjustment of pressure switch
>>
>>
>> Does anyone know what the air pressure is in the airbags when the coach is
>> in "hold" setting at normal height?
>>
>> The reason I ask is that, after installing the Cinnebar air system upgrade
>> kit for Electrolevel I, which includes an in-line gauge, I discovered that
>> my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
>> at 100 and off at 120 according to the manuals.)
>>
>> If I adjust the pressure switch by backing off the adjusting nut
>> so that the
>> compressor turns off at 120psi, that will also reduce the
>> pressure at which
>> the compressor cycles back on, will it not?
>>
>> I'm wondering if the system will still function normally with the lower
>> cut-in pressure.
>>
>> Dick Guthart
>> '77 Birchaven (still ugly but getting closer to mechanically restored)
>>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Tell me more. Is this for the earlier models or all models. I was told to put
the air ride on auto for the first five minutes and then to turn the rocker to
hold. What is my warning to do the hold thing and what happens. I have been
doing this for 10 years and have had no problems. Chuck Ifd I am doing
something wrong please let me know soon.

> Some information about your problem with the air system.
>
> 1. the pressure in the air tank for an power level or Electron level 1
> system ranges from 100psi (will turn on the compressor) to 120psi
> (compressor shutoff).
>
> 2. If you want to lower the high pressure setting back off the large nut
> (not turn it in) on the large spring. By playing with the small screw
> (differential setting) and the large nut you should be able to get the
> compressor to go on at 100psi and off at 120psi. The small screw has nothing
> to do with the low pressure setting.
>
> 3. The air has no way to get back into the tank since the power level or
> electro level contol valves or solenoids which ever is the case restricts it.
>
> 4. The manuals are very specific about not driving with the controls in
> hold. Depending on the driving conditions, speed etc an overload condition
> can develop on the front tires.
>
> Hope this helps.
>

> >Richard --
> >
> >Air bag pressure will vary with the weight of the coach. You are trying to
> >maintain a fixed height, so more pressure may be required to do that. My '77
> >Kingsley averages between 80 and 90 pounds in the air bags themselves.
> >
> >Your tank pressure, which is what you're seeing with that gauge, should be
> >80 to 120
> >
> >142# is too much. Back the larger nut off on the big spring in the pressure
> >switch. 120# is plenty. More than that, and you'll blow out your air bags if
> >you use the raise setting of the EL I.
> >
> >If I remember correctly, there is a smaller screw that controls the
> >differential. Differential is the turn on point for the compressor. Turning
> >it down (tighter) should make the differential less, but that can also make
> >the turn off point be higher. You have to kind of fiddle with it to get it
> >just right.
> >
> >Based on my experience, you need to have the compressor turn on at 80 to 85#
> >to have enough tank pressure to get and keep the right ride height with a
> >heavier load.
> >
> >Here's the reason: the heavier load equals higher bag pressure.
> >
> >The leveling valves are calling for more air to be sent to the bags, but the
> >load on the bags pushes air pressure back into the holding tank. Then, the
> >compressor doesn't run.
> >
> >The ride height never goes up when the compressor won't run. The compressor
> >won't run when the pressure switch is satisfied. The net effect is that the
> >ride height is too low under load, which throws off your front end steering
> >geometry and alignment.
> >
> >All that said, I've assumed you "set level to auto" and are not a "set level
> >to hold" type of guy. If you're a 'holder' then none of this matters,
> >because your entire EL I system is turned off. If your rear air bags leak
> >down any at all, you loose ride height. The system can only level itself in
> >the 'auto' setting and maintain a constant ride height in the 'auto'
> >setting.
> >
> >The owners' manual, the light on the dash and the people on this list are
> >all divided on the proper operation of the level switch.
> >
> >I struggled with these concepts for a long time before finally figuring it
> >out. I could never consistently get the right ride height until I fixed my
> >pressure switch problem.
> >
> >Mark Grady
> >'77 Kingsley
> >North Webster, IN
> >mgrady
> >
> >
> >> -----Original Message-----
> >> From: owner-gmcmotorhome
> >> [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
> >> Sent: Thursday, November 19, 1998 1:26 PM
> >> To: gmcmotorhome
> >> Subject: GMC: air bag pressure & adjustment of pressure switch
> >>
> >>
> >> Does anyone know what the air pressure is in the airbags when the coach is
> >> in "hold" setting at normal height?
> >>
> >> The reason I ask is that, after installing the Cinnebar air system upgrade
> >> kit for Electrolevel I, which includes an in-line gauge, I discovered that
> >> my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
> >> at 100 and off at 120 according to the manuals.)
> >>
> >> If I adjust the pressure switch by backing off the adjusting nut
> >> so that the
> >> compressor turns off at 120psi, that will also reduce the
> >> pressure at which
> >> the compressor cycles back on, will it not?
> >>
> >> I'm wondering if the system will still function normally with the lower
> >> cut-in pressure.
> >>
> >> Dick Guthart
> >> '77 Birchaven (still ugly but getting closer to mechanically restored)
> >>
> >
> >
> >
> Tom & Marg Warner
> Vernon Center NY
> 1976 palmbeach
 
I tried the auto on all the time once and the compressors came on periodically.
When I go to my destination the air bags had the coach pretty high in the rear.
Chuck Is something wrong here? How do I fix it? I have always used the fine
minute to get the height right and then turned the rocker switch to hold. I
have the 78 model.

> Richard --
>
> Air bag pressure will vary with the weight of the coach. You are trying to
> maintain a fixed height, so more pressure may be required to do that. My '77
> Kingsley averages between 80 and 90 pounds in the air bags themselves.
>
> Your tank pressure, which is what you're seeing with that gauge, should be
> 80 to 120
>
> 142# is too much. Back the larger nut off on the big spring in the pressure
> switch. 120# is plenty. More than that, and you'll blow out your air bags if
> you use the raise setting of the EL I.
>
> If I remember correctly, there is a smaller screw that controls the
> differential. Differential is the turn on point for the compressor. Turning
> it down (tighter) should make the differential less, but that can also make
> the turn off point be higher. You have to kind of fiddle with it to get it
> just right.
>
> Based on my experience, you need to have the compressor turn on at 80 to 85#
> to have enough tank pressure to get and keep the right ride height with a
> heavier load.
>
> Here's the reason: the heavier load equals higher bag pressure.
>
> The leveling valves are calling for more air to be sent to the bags, but the
> load on the bags pushes air pressure back into the holding tank. Then, the
> compressor doesn't run.
>
> The ride height never goes up when the compressor won't run. The compressor
> won't run when the pressure switch is satisfied. The net effect is that the
> ride height is too low under load, which throws off your front end steering
> geometry and alignment.
>
> All that said, I've assumed you "set level to auto" and are not a "set level
> to hold" type of guy. If you're a 'holder' then none of this matters,
> because your entire EL I system is turned off. If your rear air bags leak
> down any at all, you loose ride height. The system can only level itself in
> the 'auto' setting and maintain a constant ride height in the 'auto'
> setting.
>
> The owners' manual, the light on the dash and the people on this list are
> all divided on the proper operation of the level switch.
>
> I struggled with these concepts for a long time before finally figuring it
> out. I could never consistently get the right ride height until I fixed my
> pressure switch problem.
>
> Mark Grady
> '77 Kingsley
> North Webster, IN
> mgrady
>
> > -----Original Message-----
> > From: owner-gmcmotorhome
> > [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
> > Sent: Thursday, November 19, 1998 1:26 PM
> > To: gmcmotorhome
> > Subject: GMC: air bag pressure & adjustment of pressure switch
> >
> >
> > Does anyone know what the air pressure is in the airbags when the coach is
> > in "hold" setting at normal height?
> >
> > The reason I ask is that, after installing the Cinnebar air system upgrade
> > kit for Electrolevel I, which includes an in-line gauge, I discovered that
> > my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
> > at 100 and off at 120 according to the manuals.)
> >
> > If I adjust the pressure switch by backing off the adjusting nut
> > so that the
> > compressor turns off at 120psi, that will also reduce the
> > pressure at which
> > the compressor cycles back on, will it not?
> >
> > I'm wondering if the system will still function normally with the lower
> > cut-in pressure.
> >
> > Dick Guthart
> > '77 Birchaven (still ugly but getting closer to mechanically restored)
> >
 
I have seen the air bag extenders but as an engineer I ask myself what the
safety factor now is on the arms that hold the air bags? You are extending
the arms by 3 inches. Has Cinnabar looked at this modification?

>In a message dated 11/19/98 5:25:15 PM Central Standard Time, warner
>writes:
>
> >Air bag pressure will vary with the weight of the coach. You are trying to
> >maintain a fixed height, so more pressure may be required to do that. My '77
> >Kingsley averages between 80 and 90 pounds in the air bags themselves.
> > >>
>I'm a believer in the air bag extenders which raise the air bags close to 3
>inches. This added leverage allows them to maintain ride heigth without as
>much air pressure, hence a softer ride.
>Justin, 77 PB
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Chuck I am of the understanding that all of the air systems, Power level,
electro Level 1 and electro level 2(not many made) operate on the same basic
principle. Main difference is that the Power level uses a manual switch to
direct air from the air reservoir to and from the air bags, and the electro
level systems uses rocker switches and a series of solenoids to direct the
air flow to and from the bags. When first starting the coach the switch
should be in the auto position and the air bags will fill up (if any of the
system leaks) until the height control shuts the air off, to each bag as the
correctly set height is reached. The air compressor will cylce on when ever
the air tank pressure falls below 100#, and shut off when it rises to 120
The electro level systems have different high and low settings I believe as
high as 150

When the coach is put in drive, the warning light should come on the dash
telling you to put the valves in auto. This allows the coach air system to
add or remove air from the bags as the conditions warrant. If the controls
are set in hold, air is never sent to the bags. If there is a slow leak in
a bag that side will slowly go down, overloading the tires on that side,
possiblly increasing to the point where it is possible to blow a tire.
When talking to Wes Cauglin about this subject he noted that running the
coach in hold is not good and results in faster and abnormal wear of the tires.

I have only glanced at the electro level systems but think this is a correct
explanation for them also. Hope this helps.

>Tell me more. Is this for the earlier models or all models. I was told to put
>the air ride on auto for the first five minutes and then to turn the rocker to
>hold. What is my warning to do the hold thing and what happens. I have been
>doing this for 10 years and have had no problems. Chuck Ifd I am doing
>something wrong please let me know soon.
>

>
>> Some information about your problem with the air system.
>>
>> 1. the pressure in the air tank for an power level or Electron level 1
>> system ranges from 100psi (will turn on the compressor) to 120psi
>> (compressor shutoff).
>>
>> 2. If you want to lower the high pressure setting back off the large nut
>> (not turn it in) on the large spring. By playing with the small screw
>> (differential setting) and the large nut you should be able to get the
>> compressor to go on at 100psi and off at 120psi. The small screw has nothing
>> to do with the low pressure setting.
>>
>> 3. The air has no way to get back into the tank since the power level or
>> electro level contol valves or solenoids which ever is the case restricts it.
>>
>> 4. The manuals are very specific about not driving with the controls in
>> hold. Depending on the driving conditions, speed etc an overload condition
>> can develop on the front tires.
>>
>> Hope this helps.
>>

>> >Richard --
>> >
>> >Air bag pressure will vary with the weight of the coach. You are trying to
>> >maintain a fixed height, so more pressure may be required to do that. My '77
>> >Kingsley averages between 80 and 90 pounds in the air bags themselves.
>> >
>> >Your tank pressure, which is what you're seeing with that gauge, should be
>> >80 to 120
>> >
>> >142# is too much. Back the larger nut off on the big spring in the pressure
>> >switch. 120# is plenty. More than that, and you'll blow out your air bags if
>> >you use the raise setting of the EL I.
>> >
>> >If I remember correctly, there is a smaller screw that controls the
>> >differential. Differential is the turn on point for the compressor. Turning
>> >it down (tighter) should make the differential less, but that can also make
>> >the turn off point be higher. You have to kind of fiddle with it to get it
>> >just right.
>> >
>> >Based on my experience, you need to have the compressor turn on at 80 to 85#
>> >to have enough tank pressure to get and keep the right ride height with a
>> >heavier load.
>> >
>> >Here's the reason: the heavier load equals higher bag pressure.
>> >
>> >The leveling valves are calling for more air to be sent to the bags, but the
>> >load on the bags pushes air pressure back into the holding tank. Then, the
>> >compressor doesn't run.
>> >
>> >The ride height never goes up when the compressor won't run. The compressor
>> >won't run when the pressure switch is satisfied. The net effect is that the
>> >ride height is too low under load, which throws off your front end steering
>> >geometry and alignment.
>> >
>> >All that said, I've assumed you "set level to auto" and are not a "set level
>> >to hold" type of guy. If you're a 'holder' then none of this matters,
>> >because your entire EL I system is turned off. If your rear air bags leak
>> >down any at all, you loose ride height. The system can only level itself in
>> >the 'auto' setting and maintain a constant ride height in the 'auto'
>> >setting.
>> >
>> >The owners' manual, the light on the dash and the people on this list are
>> >all divided on the proper operation of the level switch.
>> >
>> >I struggled with these concepts for a long time before finally figuring it
>> >out. I could never consistently get the right ride height until I fixed my
>> >pressure switch problem.
>> >
>> >Mark Grady
>> >'77 Kingsley
>> >North Webster, IN
>> >mgrady
>> >
>> >
>> >> -----Original Message-----
>> >> From: owner-gmcmotorhome
>> >> [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
>> >> Sent: Thursday, November 19, 1998 1:26 PM
>> >> To: gmcmotorhome
>> >> Subject: GMC: air bag pressure & adjustment of pressure switch
>> >>
>> >>
>> >> Does anyone know what the air pressure is in the airbags when the coach is
>> >> in "hold" setting at normal height?
>> >>
>> >> The reason I ask is that, after installing the Cinnebar air system upgrade
>> >> kit for Electrolevel I, which includes an in-line gauge, I discovered that
>> >> my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
>> >> at 100 and off at 120 according to the manuals.)
>> >>
>> >> If I adjust the pressure switch by backing off the adjusting nut
>> >> so that the
>> >> compressor turns off at 120psi, that will also reduce the
>> >> pressure at which
>> >> the compressor cycles back on, will it not?
>> >>
>> >> I'm wondering if the system will still function normally with the lower
>> >> cut-in pressure.
>> >>
>> >> Dick Guthart
>> >> '77 Birchaven (still ugly but getting closer to mechanically restored)
>> >>
>> >
>> >
>> >
>> Tom & Marg Warner
>> Vernon Center NY
>> 1976 palmbeach
>
>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
You need to adjust the height control valve and their is a procedure in the
manual to follow. There are 3 adjustments and they need to be done off the
coach.

>I tried the auto on all the time once and the compressors came on periodically.
>When I go to my destination the air bags had the coach pretty high in the rear.
>Chuck Is something wrong here? How do I fix it? I have always used the fine
>minute to get the height right and then turned the rocker switch to hold. I
>have the 78 model.
>

>
>> Richard --
>>
>> Air bag pressure will vary with the weight of the coach. You are trying to
>> maintain a fixed height, so more pressure may be required to do that. My '77
>> Kingsley averages between 80 and 90 pounds in the air bags themselves.
>>
>> Your tank pressure, which is what you're seeing with that gauge, should be
>> 80 to 120
>>
>> 142# is too much. Back the larger nut off on the big spring in the pressure
>> switch. 120# is plenty. More than that, and you'll blow out your air bags if
>> you use the raise setting of the EL I.
>>
>> If I remember correctly, there is a smaller screw that controls the
>> differential. Differential is the turn on point for the compressor. Turning
>> it down (tighter) should make the differential less, but that can also make
>> the turn off point be higher. You have to kind of fiddle with it to get it
>> just right.
>>
>> Based on my experience, you need to have the compressor turn on at 80 to 85#
>> to have enough tank pressure to get and keep the right ride height with a
>> heavier load.
>>
>> Here's the reason: the heavier load equals higher bag pressure.
>>
>> The leveling valves are calling for more air to be sent to the bags, but the
>> load on the bags pushes air pressure back into the holding tank. Then, the
>> compressor doesn't run.
>>
>> The ride height never goes up when the compressor won't run. The compressor
>> won't run when the pressure switch is satisfied. The net effect is that the
>> ride height is too low under load, which throws off your front end steering
>> geometry and alignment.
>>
>> All that said, I've assumed you "set level to auto" and are not a "set level
>> to hold" type of guy. If you're a 'holder' then none of this matters,
>> because your entire EL I system is turned off. If your rear air bags leak
>> down any at all, you loose ride height. The system can only level itself in
>> the 'auto' setting and maintain a constant ride height in the 'auto'
>> setting.
>>
>> The owners' manual, the light on the dash and the people on this list are
>> all divided on the proper operation of the level switch.
>>
>> I struggled with these concepts for a long time before finally figuring it
>> out. I could never consistently get the right ride height until I fixed my
>> pressure switch problem.
>>
>> Mark Grady
>> '77 Kingsley
>> North Webster, IN
>> mgrady
>>
>> > -----Original Message-----
>> > From: owner-gmcmotorhome
>> > [mailto:owner-gmcmotorhome]On Behalf Of Richard Guthart
>> > Sent: Thursday, November 19, 1998 1:26 PM
>> > To: gmcmotorhome
>> > Subject: GMC: air bag pressure & adjustment of pressure switch
>> >
>> >
>> > Does anyone know what the air pressure is in the airbags when the coach is
>> > in "hold" setting at normal height?
>> >
>> > The reason I ask is that, after installing the Cinnebar air system upgrade
>> > kit for Electrolevel I, which includes an in-line gauge, I discovered that
>> > my compressor has been cycling on at 80psi and off at 142psi! (Spec. is on
>> > at 100 and off at 120 according to the manuals.)
>> >
>> > If I adjust the pressure switch by backing off the adjusting nut
>> > so that the
>> > compressor turns off at 120psi, that will also reduce the
>> > pressure at which
>> > the compressor cycles back on, will it not?
>> >
>> > I'm wondering if the system will still function normally with the lower
>> > cut-in pressure.
>> >
>> > Dick Guthart
>> > '77 Birchaven (still ugly but getting closer to mechanically restored)
>> >
>
>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Mark & Tom:

Thanks for your responses. I've seen the large nut but didn't notice any
small screw. Will look again on Monday.

Dick Guthart
'77 Birchaven

>Back the larger nut off on the big spring in the pressure
>switch....

>If I remember correctly, there is a smaller screw that controls the
>differential.
 
Thanks. I have brand new everything and not leaks. But I will try to
run with the AUTO on and see what happens. I know I have done this
before and when I get to the destination the back end is pretty high
and no air has escaped to allow the ride height to stay at the 11 inches.
What should I look for? Apparently it is a minor adjustment of some type.
Chuck
 
Ok, When I am parked and the engine is off and the switches are in hold I have no
leaks. When I turn on the engine and turn the rocker to AUTO it pumps to the
correct level and turns it self off. while driving down the road the compressor
comes on periodically momentarily one of those words, but not for long, In the
mountains it seems to do it more. What happens is that when I get to where I am
going the coach is as high as it can get, no air has been released to keep it at
the 11 inches. I must assume at this pint I have no leaks, not even the ones I am
supposed to have. chuck

> Chuck
>
> Understand that what I am going to say is from what I have read not
> what I know. GMC was having so much trouble with the air suspension
> system that even they said to put it in hold for a while. What you want to
> do is put it in travel when you are on the road. This lets the automatic
> leveling feature work the way it was supposed to. When you put it in hold
> it adjusts to nothing. Get all the leaks out and it will work the way it
> should. Its is even fun to have the old gal hiss at you.
>
> Please understand this is the info I have read not what I have experienced.
>
> Take Care
> Arch 76 GB IL
>
> >
> > Tell me more. Is this for the earlier models or all models. I was told
> > to put
> > the air ride on auto for the first five minutes and then to turn the rocker
> > to
> > hold. What is my warning to do the hold thing and what happens. I have
> > been
> > doing this for 10 years and have had no problems. Chuck Ifd I am doing
> > something wrong please let me know soon.
> >
 
Chuck:

The 1978 model operators manual discusses the Electro Level Type I
(single compressor) and Type II (twin compressor) systems operation
beginning on p. 28. It says "The center TRAVEL switch should be in the
HOLD position.", when driving down the highway.

I have always traveled that way once the initial leveling has been
completed, without any problems.

Because there is a time delay (approximately 30 seconds, in the Type II
system anyway) in the system, I contend that while driving you'll be
long gone from anywhere that requires subsequent leveling, provided your
air bags don't loose/leak air pressure. In other words, the air
suspension system isn't that quick to react.

Paul Bartz

From: Chuck Will [mailto:willa]
Sent: Friday, November 20, 1998 11:28 AM
Subject: Re: GMC: air bag pressure & adjustment of pressure
switch (reply)

Thanks. I have brand new everything and not leaks. But I will try to
run with the AUTO on and see what happens. I know I have done this
before and when I get to the destination the back end is pretty high and
no air has escaped to allow the ride height to stay at the 11 inches.

What should I look for? Apparently it is a minor adjustment of some
type.
 
I have an auto level valve that does nothing on my electro I system (1978
version). Sooooooooooooooo,

Has anyone recently 'rebuilt' one of their auto leveling values?? Jim
Bounds says that new ones don't exsist. Lokking for advice and source for
rebuild parts..........th

>Chuck:
> ((snip))
 
Thom:

I believe the valve was common to late 70's Cadillac's with air level
control. Give the part number to a local GM dealer parts department and
they can search their data base and print out the year and models it's
common with. However, as Jim says new one's don't exist. You can scour
the salvage yards though.

Paul Bartz

- -----Original Message-----
From: Thom Hole [mailto:THHOLE]
Sent: Friday, November 20, 1998 2:31 PM
Subject: RE: GMC: air bag pressure & adjustment of pressure
switch (reply)

I have an auto level valve that does nothing on my electro I system
(1978
version). Sooooooooooooooo,

Has anyone recently 'rebuilt' one of their auto leveling values?? Jim
Bounds says that new ones don't exsist. Lokking for advice and source
for rebuild parts..........th
 
>
> In a message dated 11/19/98 5:25:15 PM Central Standard Time, warner

>
> >Air bag pressure will vary with the weight of the coach. You are trying to
> >maintain a fixed height, so more pressure may be required to do that. My '77
> >Kingsley averages between 80 and 90 pounds in the air bags themselves.
> > >>
> I'm a believer in the air bag extenders which raise the air bags close to 3
> inches. This added leverage allows them to maintain ride heigth without as
> much air pressure, hence a softer ride.
> Justin, 77 PB

JUSTIN
TELL US MORE ABOUT THE AIR BAG EXTENDERS . MY PROBLEM IS OUR
COACH IS NOT SITTING LEVEL AT ALL. AND I THINK THIS COULD BE MY ANSWER.

MURRAY
ESTERHAZY SASK CANADA
73 ELAGANZA SE
 
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